Isolate initiation counts for downloads to their own histograms and improve

chrome/browser/download/download_resource_throttle.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/download/download_resource_throttle.h"
 
 #include "base/bind.h"
+#include "chrome/browser/download/download_util.h"
 #include "content/public/browser/resource_throttle_controller.h"
 
 DownloadResourceThrottle::DownloadResourceThrottle(
     DownloadRequestLimiter* limiter,
     int render_process_id,
     int render_view_id,
     int request_id)
     : request_allowed_(false),
       request_deferred_(false) {
   limiter->CanDownloadOnIOThread(
@@ skipping 15 matching lines @@
                                                    bool* defer) {
   *defer = request_deferred_ = !request_allowed_;
 }
 
 void DownloadResourceThrottle::WillReadRequest(bool* defer) {
   *defer = request_deferred_ = !request_allowed_;
 }
 
 void DownloadResourceThrottle::ContinueDownload(bool allow) {
   request_allowed_ = allow;
+  if (allow) {
+      download_util::RecordDownloadSource(

[darin (slow to review), 2012/02/10 23:47:28]

nit: indentation

You are counting on the fact that ContinueDownload only gets called once and
that DownloadResourceThrottle is only used for downloads initiated by
navigation, right?  Those are pretty obvious pre-conditions for this code, so
maybe it is fine to just assume that.  Otherwise, maybe it is worth a comment or
even an assertion, in case someone extends this class or uses it in another
context later.  I suppose the INITIATED_BY_NAVIGATION flag could be passed to
the DownloadResourceThrottle constructor if need be.

[Randy Smith (Not in Mondays), 2012/02/12 19:19:00]

Done.

+          download_util::INITIATED_BY_NAVIGATION);
+  } else {
+      download_util::RecordDownloadCount(download_util::BLOCKED_BY_THROTTLING);
+  }
 
   if (request_deferred_) {
     if (allow) {
       controller()->Resume();
     } else {
       controller()->Cancel();
     }
   }
 }